My idling is iregular. What could be the issue?

What is your question?

My sonata 2.0 16v 95 model is idling low when cold and high when warm. There is also a vibration on the engine at low revs and fine in the higher revs. What could be the problem?

How long has your 1995 Hyundai Sonata had this problem?

Since we installed a new motor